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Monday, May 19, 2008

Over at BHA Science Tom Rees explains that a religious man may have an evolutionary advantage over the non-religioius because he has certain characteristics that better attracts a mate. But it is not because of religion directly more to do with the side effects of being religious.

Why has a peculiar feature of religion evolved: the propagation of beliefs about the world that conflict with reality? Can communication of unreal information (i.e. religious beliefs) ever confer a survival benefit? The research cited suggests that a mate may prefer a religious over a non-religious person because the religious appears to be more trustworthy or has the ability to imitate a kind parent or because he displays some sexually attractive physical or mental abilities.

A trait doesn't have to have a direct survival benefit for it to be selected for by evolution. So long as it sends a signal to the opposite sex that you have gametes that are worth getting hold of, your reproductive fitness will increase and the trait will be selected for. It's called the Green-Beard Effect, after the popular description by Dawkins in his 1979 book “The Selfish Gene” (although the idea was first proposed in 1964). All it takes is that the genes that create the signal are linked to the genes that code for something that enhances your quality as a prospective mate. Sounds unlikely, but it can happen in theory (Janse & van Ballen, 2006) and seems to happen in practice (in Californian side-blotched lizards, for example)

What on earth does this have to do with religion? Well, Prof James Dow (an Anthropologist at Oakland University) has been modelling the evolution of religion, and in particular trying to figure out why one particularly peculiar feature of religion should have evolved: the propagation of beliefs about the world that conflict with reality.

As Dow points out:

One feature of religion that seems to stand out as non-adaptive is the belief in the existence of an unseen, unverifiable world. The existence of gods, spirits, and the like cannot be verified by the senses. A belief in them makes no sense from an common evolutionary point of view. The animal whose conception of the world is out of touch with reality should be eliminated by natural selection. The one whose mental images correspond most closely to the real environment should be one to survive. The primary problem of explaining how religion has evolved through natural selection is the problem of explaining the belief in unreal things.

But such a belief system could evolve if it has beneficial effect on social organisation. So he set out to investigate in an agent based model whether communication of unreal information (i.e. religious beliefs) could ever confer a survival benefit. Essentially, the model allowed for the co-evolution of culture and genetics, to see if communicating unreal information could help the agents get better at communicating real information.

The bottom line is it didn’t. No matter how Dow tweaked it, the agents who communicated unreal information died out. But that changed when he added the Green-beard effect. This suggests that only way that communication of religious beliefs could evolve is if it is a marker of something else that signifies increased reproductive fitness. Dow explains:

It is clear from the simulation runs shown here that the key to religion's evolution is in the greenbeard effect, the ability to attract adherents. The evogod simulation does not explain why people will give benefits to others who proclaim a reality that is unverifiable. However, it tells us that if they do give such benefits, the biological evolution of religious behavior can occur.

Commitment theory takes this idea one step further and proposes that the reason that people do give such benefits is that they perceive religious folk to be more trustworthy. The results of the evogod simulation support this theory; however they do not completely eliminate other motives for commitment. The attractiveness of unreal communicators might be due to their ability to imitate a kind parent (Kirkpatrick 2005), or to the display of some sexually attractive physical or mental ability, or all three of these types of attractiveness might be in play. The simulation does clearly show that religion cannot evolve simply by stimulating cultural communication. It has to have a quality that causes others to direct communication toward the the person who communicates the most religious ideas. It suggests further research on the motives people have for communicating with, and giving benefits to communicators of religious ideas.